[Python-ideas] generic Ref class
Aaron Brady
castironpi at comcast.net
Sat Jan 12 21:21:47 CET 2008
> -----Original Message-----
> From: python-ideas-bounces+castironpi=comcast.net at python.org
> [mailto:python-ideas-bounces+castironpi=comcast.net at python.org] On Behalf
> Of Adam Atlas
>
> On 12 Jan 2008, at 15:03, Aaron Brady wrote:
> > Then:
> >
> > for x in refs( listA ):
> > x.val+= 1
> >
> > Better than:
> >
> > for i, x in enumerate( listA ):
> > listA[i]= x+ 1
>
> Don't these do different things? The latter modifies the original
> list, while the former, with your Ref class, apparently modifies (in a
> by-reference sense) a new list that is thrown away once the for loop
> is done.
Ah yes. Say:
listA= refs( range( 20 ) ) #or your list
then:
for x in listA:
x.val+= 1
Slightly slower, but useful in addition to pass to functions too:
def squareanint( intref ):
intref.val**= 2
a= 2
squareanint( a )
print a
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